package com.lcx.demo.nioday01;

import org.junit.Test;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;

/*
*一、使用NIO完成网络通信的三个核心
*
* 1.通道（Channel)：负责连接
*  java.nio.channels.Channel 接口：
*       |--SelectableChannel
*           |--SocketChannel
*           |--ServerSocketChannel
*           |--DatagramChannel
*
*           |--Pipe.SinkChannel
*           |--Pipe.SourceChannel
*
* 2.缓冲区（Buffer）：负责数据的存取
*
* 3.选择器（Selector）：是SelectableChannel的多路复用器。用于监控SelectableChannel的IO状况
*/
public class TestBlockingNIO {

    //客户端
    @Test
    public void client() throws IOException {
        //1.获取通道
        SocketChannel socketChannel = SocketChannel.open(new InetSocketAddress("127.0.0.1", 9869));

        FileChannel inChannel = FileChannel.open(Paths.get("./src/1.jpg"), StandardOpenOption.READ);

        //2.分配指定大小的缓冲区
        ByteBuffer buf = ByteBuffer.allocate(1024);

        //3.读取本地文件，并发送到服务器
        while(inChannel.read(buf)!=-1){
            buf.flip();
            socketChannel.write(buf);
            buf.clear();
        }

        //4.关闭通道
        inChannel.close();
        socketChannel.close();
    }

    //服务端
    @Test
    public void server() throws IOException {
        //获取通道
        ServerSocketChannel ssChannel = ServerSocketChannel.open();

        FileChannel outChannel = FileChannel.open(Paths.get("2.jpg"),StandardOpenOption.WRITE,StandardOpenOption.CREATE);

        //绑定连接
        ssChannel.bind(new InetSocketAddress(9869));

        //获取客户端链接的通道
        SocketChannel sChannel = ssChannel.accept();

        //分配指定大小的缓冲区
        ByteBuffer buf = ByteBuffer.allocate(1024);

        //连接客户端的数据并保存到本地
        while (sChannel.read(buf)!=-1){
            buf.flip();
            outChannel.write(buf);
            buf.clear();
        }
        outChannel.close();
        sChannel.close();
        ssChannel.close();
    }
}
